Catheter

ABSTRACT

[Object] To provide a catheter having a simple structure capable of excising an atheroma in a blood vessel and capable of obtaining ultrasonic images of a blood vessel. 
     [Solution] A catheter  10  has a shaft  11  having an opening  20  in a part of the side wall on the distal end side, a cutter  12  which is located in the vicinity of the opening  20  in the internal space of the shaft  11  and which can move in the axial direction  101  of the shaft  11 , a balloon  23  which is disposed on the side opposite to the opening  20  with respect to the axis of the shaft  11  and which outwardly expands from the side wall of the shaft  11 , and a phased array ultrasound probe  17  disposed along the circumferential direction  102  of the outer peripheral surface of the side wall in the vicinity of the opening  20  at least on the same side as the side where the opening  20  is provided with respect to the axis of the shaft  11.

TECHNICAL FIELD

The present invention relates to a catheter to be inserted into a bloodvessel in order to excise an atheroma adhering to the inner wall of ablood vessel.

BACKGROUND ART

Heretofore, medical treatment of inserting a catheter into a bloodvessel to excise an atheroma generated in the blood vessel has beenperformed. An analysis of whether or not an atheroma is generated in ablood vessel has been performed by inserting a catheter having anultrasound probe into the blood vessel to obtain an ultrasonic image.Moreover, for the analysis of whether or not an atheroma is present in ablood vessel, image analysis by an optical coherence tomography(hereinafter also referred to as “OCT”), for example, can be conducted(Patent Literature 4).

In order to excise an atheroma found in a blood vessel, an atheromaexcision catheter has been used which excises an atheroma with a cutterthrough an opening in the side wall. The atheroma excision catheter isinserted into a blood vessel to the position where an opening faces theatheroma, and then a balloon provided in the vicinity of the opening isexpanded, so that the opening is brought close to the atheroma, so thatthe atheroma enters a lumen of the atheroma excision catheter throughthe opening. In the lumen of the atheroma excision catheter, a cutter ismovably provided in the axial direction. The cutter receives drivetransmitted from a motor to be rotated in the lumen. The cutter is movedin the lumen while being rotated to thereby excise the atheroma enteringthe lumen. The excised atheroma is accommodated in the lumen of theatheroma excision catheter (Patent Literatures 1 and 2).

In the excision of the atheroma described above, ultrasonic images areobtained immediately before the excision in order to align the positionsof the atheroma and the opening of the atheroma excision catheter.Thereafter, the atheroma is excised by the atheroma excision catheter.Furthermore, ultrasonic images are obtained again in order to check thestate of the blood vessel after the excision of the atheroma. When it istemporarily judged that the atheroma is not sufficiently excised, theremaining atheroma is excised again by the atheroma excision catheter,and thereafter the state of the blood vessel is checked again. In suchan operation, the catheter having the ultrasound probe and the atheromaexcision catheter are alternately inserted into the blood vessel, whichis likely to complicate the operation. In view of such circumstances, acatheter has been devised in which an atheroma excision catheter isprovided with an ultrasound probe capable of rotating around the axis(Patent Literature 3).

CITATION LIST Patent Literature

-   [Patent Literature 1] Japanese Unexamined Patent Publication    Application No. 6-30943-   [Patent Literature 2] Japanese Unexamined Patent Publication    Application No. 5-56984-   [Patent Literature 3] Japanese Unexamined Patent Application    Publication (Translation of PCT Application) No. 9-182754-   [Patent Literature 4] Japanese Unexamined Patent Application    Publication (Translation of PCT Application) No. 2008-523954

SUMMARY OF INVENTION Technical Problems

The atheroma excision catheter provided with an ultrasound probedescribed above has problems that the attachment structure of the cutterand the ultrasound probe and a structure for rotating each of the cutterand the ultrasound probe are complicated, the catheter size increases,and instability of the operation due to failures and the like increases.

In the excision of the atheroma described above, in order to align thepositions of the atheroma and the opening of the atheroma excisioncatheter, image analysis by the OCT is conducted before the excision,and thereafter, the atheroma is excised by the atheroma excisioncatheter. Furthermore, image analysis by the OCT is conducted again inorder to check the state of the blood vessel after the excision of theatheroma. When it is temporarily judged that the atheroma is notsufficiently excised, the remaining atheroma is excised again by theatheroma excision catheter, and thereafter the state of the blood vesselis checked again. In such an operation, the catheter for the OCT and theatheroma excision catheter are alternately inserted into the bloodvessel, which is likely to complicate the operation.

The present invention has been made in view of such circumstances. It isan object of the present invention to provide a catheter having a simplestructure capable of excising an atheroma in a blood vessel and capableof obtaining ultrasonic images of the blood vessel.

It is another object of the present invention to provide a catheterhaving a simple structure capable of excising an atheroma in a bloodvessel and capable of obtaining images of the blood vessel by the OCT.

Solution to Problems

(1) A catheter according to the present invention has a tube body havingan opening in a part of the side wall on the distal end side, a cutterwhich is located in the vicinity of the opening in the internal space ofthe tube body and which can move in the axial direction of the tubebody, a balloon which is disposed on a side opposite to the opening withrespect to the axis of the tube body and which outwardly expands fromthe side wall of the tube body, and a phased array ultrasound probedisposed along the circumferential direction of the outer peripheralsurface of the side wall in the vicinity of the opening at least on thesame side as the side where the opening is provided with respect to theaxis of the tube body.

The catheter is inserted into a blood vessel from the distal end side.Due to the fact that the balloon is expanded in a state where theopening of the tube body is aligned with an atheroma in the bloodvessel, the tube body is fixed to the blood vessel, so that the atheromaenters the internal space of the tube body from the opening. By thecutter moved in the axial direction of the tube body, the atheromaentering the internal space of the tube body is excised. By theultrasound probe disposed in the vicinity of the opening of the tubebody, ultrasonic images of the excised atheroma are obtained.

(2) The catheter further has an outer tube body which is provided on theoutside of the tube body and which can relatively move in the axialdirection with respect to the tube body, in which the ultrasound probemay be provided on the outer tube body.

Since the ultrasound probe can move in the blood vessel in connectionwith the relative movement of the outer tube body, ultrasonic images ofcross sections or partial cross sections of the blood vessel differentin the position in the length direction can be obtained by moving theultrasound probe with respect to the atheroma.

(3) The outer tube body has a notch portion in which a partcorresponding to the balloon is cut out, and a support portion which isdisposed on a side opposite to the notch portion with respect to theaxis of the outer tube body and which can be moved to a first positionwhere the support portion covers the opening and a second position wherethe support portion opens the opening by the relative movement, in whichthe ultrasound probe is provided on the support portion and the notchportion may not abut on the balloon in the state of being outwardlyexpanded at the first position.

Even when the outer tube body is relatively moved to the first positionwhere the outer tube body is overlapped with the opening in the statewhere the balloon is expanded, the outer tube body and the balloon donot interfere with each other by the notch portion. In the supportportion at the first position, the atheroma located at a positioncorresponding to the opening and the ultrasound probe face each other,so that ultrasonic images of the atheroma can be obtained.

(4) The ultrasound probe may be fixed on the distal end side relative tothe opening in the tube body.

(5) The ultrasound probe may be fixed on the proximal end side relativeto the opening in the tube body.

(6) A catheter according to the present invention has a tube body havingan opening in a part of the side wall on the distal end side, a cutterwhich is located in the vicinity of the opening in the internal space ofthe tube body and which can move in the axial direction of the tubebody, a torque shaft which is inserted into and passed through theinternal space of the tube body and is connected to the cutter in such amanner as to be able to transmit a rotation torque to the cutter, alightguide material provided along the torque shaft, a reflective materialwhich reflects light emitted from the light guide material in a seconddirection crossing a first direction in which the light guide materialis extended, and a balloon which is disposed on a side opposite to theopening with respect to the axis of the tube body and outwardly expandsfrom the side wall of the tube body.

The catheter is inserted into a blood vessel from the distal end side.Due to the fact that the balloon is expanded in a state where theopening of the tube body is aligned with an atheroma in the bloodvessel, the tube body is fixed to the blood vessel, so that the atheromaenters the internal space of the tube body from the opening. By thecutter moved in the axial direction of the tube body, the atheromaentering the internal space of the tube body is excised. Light emittedfrom the light guide material provided along the torque shaft isreflected by the reflective material to be emitted to the blood vessel.Due to the fact that the reflected light from the blood vessel istreated as an interference signal by an OCT system through thereflective material and the light guide material, images of the bloodvessel in the vicinity of the atheroma are obtained.

(7) Preferably, the light guide material and the reflective material aredisposed in the internal space of the torque shaft and the reflectivematerial emits light reflected in the second direction to the outside ofthe torque shaft through the opening formed in the side wall of thetorque shaft.

Thus, light can be guided to be reflected in the torque shaft.

(8) Preferably, the light guide material and the reflective material canbe rotated integrally with the torque shaft.

Thus, the excision of an atheroma and the OCT can be realized bycontrolling the number of rotations of a rotating device, such as amotor, connected to the torque shaft.

(9) Preferably, the light guide material and the reflective material canmove integrally with the torque shaft along the first direction.

Thus, images of a blood vessel can be obtained along the firstdirection.

(10) Preferably, the light guide material and the reflective materialare disposed in the internal space of the torque shaft.

Thus, the light guide material and the reflective material are coveredwith the torque shaft to be protected, and therefore the light guidematerial and the reflective material are hard to be damaged.

(11) Preferably, the light guide material and the reflective materialare disposed on the outer peripheral surface side of the torque shaft.

Thus, even when a guide wire is inserted into and passed through theinternal space of the torque shaft, light reflected from the reflectivematerial is not blocked by the guide wire.

(12) Preferably, a guide wire lumen is provided along the tube body.

Thus, the catheter can be inserted into a blood vessel along the guidewire.

Advantageous Effects of Invention

According to the catheter of the present invention, an atheroma in ablood vessel can be excised and ultrasonic images of the blood vesselcan be obtained by a simple structure.

Moreover, according to the catheter of the present invention, anatheroma in a blood vessel can be excised and images of the blood vesselby the OCT can be obtained by a simple structure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view illustrating the external configuration of a catheter10 in a state where a balloon 23 is contracted.

FIG. 2 is an enlarged cross sectional view illustrating the internalconfiguration in the vicinity of a distal end portion 13 of the catheter10.

FIG. 3 is a schematic view illustrating a state where the balloon 23 isexpanded in a blood vessel 50.

FIG. 4 is a schematic view illustrating a state where a support portion44 is located at a first position after an atheroma 51 is excised in theblood vessel 50.

FIG. 5 is a view illustrating a modification of the catheter 10.

FIG. 6 is a view illustrating a modification of the catheter 10.

FIG. 7 is a view illustrating the external configuration of a catheter210 in a state where a balloon 223 is contracted.

FIG. 8 is an enlarged cross sectional view illustrating the internalconfiguration in the vicinity of a distal end portion 213 of thecatheter 210.

FIG. 9 is a schematic view illustrating a state where the balloon 223 isexpanded in the blood vessel 50.

FIG. 10 is a schematic view illustrating the state where the atheroma 51is excised in the blood vessel 50.

FIG. 11 is an enlarged cross sectional view illustrating a modificationof the catheter 210.

DESCRIPTION OF EMBODIMENTS

Hereinafter, preferable embodiments of the present invention aredescribed. It is a matter of course that the embodiments merely describeone embodiment of the present invention and the embodiments can bealtered insofar as the scope of the present invention is not altered.

First Embodiment

As illustrated in FIGS. 1 and 2, a catheter 10 has a shaft 11, a cutter12 provided in the shaft 11, a distal end portion 13 configuring thedistal end of the shaft 11, a proximal end portion 14 connected to theproximal end of the shaft 11, an actuator 15 which gives rotary drive tothe cutter 12, an IVUS shaft 16, and an ultrasound probe 17 provided onthe IVUS shaft 16. The catheter 10 is used as a medical instrument whichis inserted into a blood vessel to excise an atheroma or photographsultrasonic images of a blood vessel.

The shaft 11 is a tube capable of containing the cutter 12 thereinside.The shaft 11 is configured from a surgical stainless steel circular tubeor a synthetic resin circular tube, for example, and has flexibilitywhich allows the shaft 11 to be elastically curved corresponding to thecurved shape of a blood vessel. The distal end and the proximal end ofthe shaft 11 each are opened. The outer diameter of the shaft 11 is setaccording to the inner diameter of a blood vessel into which the shaft11 is to be inserted, e.g., coronary arteries. The inner diameter of theshaft 11 is set according to the outer diameter of the cutter 12. Theouter diameter and the inner diameter of the shaft 11 are almost uniformover the axial direction 101 of the shaft 11. The length in the axialdirection 101 of the shaft 11 is set in consideration of the length fromcatheter insertion portions, such as the human limbs, to the affectedportion.

As illustrated in FIG. 2, an opening 20 is formed in the vicinity of thedistal end portion 13 in the shaft 11. The opening 20 is formed bycutting out a part of the side wall of the shaft 11. The shape and thesize of the opening 20 are set in consideration of the shape and thesize of an atheroma which is probably formed in the affected portion.The shaft 11 is equivalent to the tube body.

As illustrated in FIG. 2, the cutter 12 is provided in the vicinity ofthe opening 20 in the internal space of the shaft 11. The cutter 12 hasa cutting portion 21 and a shaft 22. The cutting portion 21 has anapproximately cylindrical shape and the outer diameter is a littlesmaller than the inner diameter of the shaft 11. On the distal end sideof the cutting portion 21, a plurality of blades are formed in such amanner as to radially extend from the center. Although not illustratedin FIG. 2, a through-hole is formed along the axial direction 101 in thecenter of the cutting portion 21. The shaft 22 is extended from theproximal end of the cutting portion 21 to the outside of the proximalend portion 14. The shaft 22 is a long and narrow tube and the internalspace communicates with the through-hole of the cutting portion 21. Theinternal space of the shaft 22 and the through-hole of the cuttingportion 21 are configured so that a guide wire is inserted into andpassed through the internal space and the through-hole.

As illustrated in FIG. 1, the shaft 22 is connected to the actuator 15.Due to the fact that the shaft 22 receives drive transmitted from theactuator 15 to rotate, the cutting portion 21 rotates. Due to the factthat the shaft 22 is moved in the axial direction 101, the cuttingportion 21 moves in the axial direction 101 in the internal space of theshaft 11.

As illustrated in FIGS. 1 and 2, a balloon 23 is provided at a positionopposite to the opening 20 with respect to the axis of the shaft 11. Theballoon 23 can outwardly expand from the side wall of the shaft 11 andis folded and stuck to the side wall of the shaft 11 until the catheter10 is inserted into a blood vessel. As raw materials of the balloon 23,materials having biocompatibility are preferable. Specific examples ofthe materials include polyurethane, polyethylene, polyester,polypropylene, polyamide, polyamide elastomer, polytetrafluoroethylene,polyvinylidene fluoride, and the like.

As illustrated in FIG. 2, the proximal end side of the balloon 23 isconnected to a tube body for balloon 24 provided along the side wall ofthe shaft 11. The internal space of the tube body for balloon 24 iscaused to communicate with the internal space of the balloon 23. Thetube body for balloon 24 is extended to the proximal end portion 14 andthe internal space of the tube body for balloon 24 is connected to aport 41 of the proximal end portion 14. Due to the fact that liquid,such as physiological saline, injected from the port 41 of the proximalend portion 14 flows into the balloon 23, the balloon 23 is expanded ina blood vessel. The tube body for balloon 24 is a molded body offlexible plastic which can be elastically deformed, such as polyamide,polyamide elastomer, and polyetheramide.

As illustrated in FIGS. 1 and 2, the distal end portion 13 is connectedto the distal end of the shaft 11. As illustrated in FIG. 2, the distalend portion 13 has a blade tube 31, a reduced diameter portion 32, and adistal end tip 33.

As illustrated in FIGS. 1 and 2, the blade tube 31 is a circular tube inwhich both sides are opened. The blade tube 31 is connected to thedistal end of the shaft 11 and the internal space thereof is caused tocommunicate with the internal space of the shaft 11. The blade tube 31is one in which flexible plastic which can be elastically deformed, suchas polyamide, polyamide elastomer, and polyetheramide, is reinforcedwith a core material 34. The core material 34 is embedded in the sidewall of the blade tube 31. The core material 34 is formed into acylindrical shape by braiding wire rods, such as surgical stainlesssteel, into a mesh. The inner diameter of the blade tube 31 is almostequal to the outer diameter of the shaft 11 and the blade tube 31 isfitted to the distal end of the shaft 11 from the outside. The outerdiameter and the inner diameter of the blade tube 31 are almost uniformover the axial direction 101. In each figure other than FIG. 1, the corematerial 34 is not illustrated.

As illustrated in FIGS. 1 and 2, the reduced diameter portion 32 is acircular tube in which both sides are opened and the outer diameterdecreases in a tapered shape. The reduced diameter portion 32 isconnected to the distal end of the blade tube 31 and the internal spacethereof is caused to communicate with the internal space of the bladetube 31. The reduced diameter portion 32 contains flexible plastic whichcan be elastically deformed, such as polyamide and polyetheramide. Theinner diameter on the proximal end side of the reduced diameter portion32 is almost equal to the outer diameter of the distal end of the bladetube 31. The reduced diameter portion 32 is fitted to the distal end ofthe blade tube 31 from the outside, and then thermally fused thereto.The inner diameter on the distal end side of the reduced diameterportion 32 is almost equal to the outer diameter of the central portionof the distal end tip 33. On the distal end side of the reduced diameterportion 32, the thickness decreases toward the distal end side.

As illustrated in FIGS. 1 and 2, the distal end tip 33 is a circulartube in which both sides are opened and the outer diameter on a proximalend 36 side increases in a tapered shape. The distal end tip 33 isconnected to the distal end of the reduced diameter portion 32 and theinternal space thereof is caused to communicate with the internal spaceof the reduced diameter portion 32. The distal end 35 of the distal endtip 33 is projected from the distal end of the reduced diameter portion32 to the outside in the axial direction 101. The proximal end 36 sideof the distal end tip 33 is extended in the axial direction 101 in theinternal space of the reduced diameter portion 32 and the proximal end36 reaches the internal space of the blade tube 31. More specifically, aportion including a distal end side portion of the blade tube 31 and thereduced diameter portion 32 has a double tube structure in which theblade tube 31 and the reduced diameter portion 32 serve as the outerside and the distal end tip 33 serves as the inner side.

Although the diameter of the distal end tip 33 is increased on theproximal end 36 side, the outer diameter and the inner diameter of theother portion are almost uniform. The outer diameter of the uniformportion is smaller than the inner diameter of the blade tube 31 and isalmost equal to the inner diameter of the distal end of the reduceddiameter portion 32. Although the diameter of the proximal end 36 sideis increased, the maximum diameter is smaller than the inner diameter ofthe blade tube 31.

The distal end tip 33 contains flexible plastic which can be elasticallydeformed, such as polyamide and polyetheramide. The distal end tip 33 isinserted into the distal end of the reduced diameter portion 32, andthen thermally fused thereto. On the distal end of the distal end tip33, a marker which can be confirmed by X-rays or the like may beprovided.

The proximal end portion 14 is provided on the proximal end of the shaft11. The proximal end portion 14 is a cylindrical member having aninternal space continuing to the internal space of the shaft 11. Theproximal end portion 14 is a molded body of resin, such as polypropyleneor ABS. The proximal end portion 14 may serve as a handle in anoperation of inserting and removing the shaft 11 into/from a bloodvessel.

The proximal end portion 14 is provided with the port 41 extended in adirection crossing the axial direction 101. Another device, such as asyringe, is connected to the port 41, and then fluid, such asphysiological saline, which is flown in and out from the device, flowsin and out of the tube body for balloon 24 from the proximal end portion14. The proximal end portion 14 may be provided with another portcontinuing to the internal space of the shaft 11. Such a port is usedfor the purpose of, for example, collecting an excised atheroma enteringthe inside of the shaft 11.

From an opening on the proximal end side of the proximal end portion 14,the shaft 22 of the cutter 12 is extended. The actuator 15 is connectedto the shaft 22. In the actuator 15, a motor, a battery, and the likeare built. To the shaft 22, rotation of the motor of the actuator 15 istransmitted.

As illustrated in FIGS. 1 and 2, the IVUS shaft 16 is provided on theoutside of the shaft 11. The IVUS shaft 16 is a tube which allows theinsertion of the shaft 11 into the IVUS shaft 16 in such a manner thatthe shaft 11 can relatively move in the axial direction 101. The IVUSshaft 16 is configured from a surgical stainless steel circular tube ora synthetic resin circular tube, for example, and has flexibility whichallows the IVUS shaft 16 to be elastically curved corresponding to thecurved shape of a blood vessel. The distal end and the proximal end ofthe IVUS shaft 16 each are opened. The outer diameter of the IVUS shaft16 is set according to the inner diameter of a blood vessel into whichthe IVUS shaft 16 is to be inserted, e.g., coronary arteries. The innerdiameter of the IVUS shaft 16 is set according to the outer diameter ofthe shaft 11. The outer diameter and the inner diameter of the IVUSshaft 16 are almost uniform over the axial direction 101. The length inthe axial direction 101 of the IVUS shaft 16 is a little shorter thanthe length in the axial direction 101 of the shaft 11. Therefore, in thestate where the IVUS shaft 16 is moved to the proximal end side withrespect to the shaft 11 until the IVUS shaft 16 abuts on the proximalend portion 14, a distal end side relative to the opening 20 of theshaft 11 is projected from the distal end of the IVUS shaft 16 to beexposed to the outside as illustrated in FIG. 1. The IVUS shaft 16 isequivalent to the outer tube body.

As illustrated in FIG. 2, a notch portion 43 extending to the proximalend side along the axial direction 101 is formed at a position on a sidecorresponding to the side of the balloon 23 of the shaft 11 in thedistal end portion of the IVUS shaft 16. The length in thecircumferential direction 102 of the notch portion 43 is longer than thelength in the circumferential direction 102 of the balloon 23 and aboutthe half in the circumferential direction 102 of the IVUS shaft 16 iscut out. The length in the axial direction 101 of the notch portion 43is a length in which the notch portion 43 does not abut on the balloon23 in the state (FIG. 4) where the distal end portion of the IVUS shaft16 is relatively moved to the distal end side with respect to the shaft11 to a position where the distal end portion of the IVUS shaft 16covers the opening 20 and is almost equal to the length in the axialdirection 101 of the opening 20.

A portion which is formed into an approximately half tube shape by thenotch portion 43 of the distal end portion of the IVUS shaft 16 is asupport portion 44 for the ultrasound probe 17. The support portion 44is located on the same side as the side on which the opening 20 isprovided of the shaft 11 in the circumferential direction 102. When theIVUS shaft 16 is moved to the distal end side of the shaft 11, thesupport portion 44 is located at a first position (FIG. 4) where thesupport portion 44 covers the opening 20. When the IVUS shaft 16 ismoved to the proximal end side of the shaft 11, the support portion 44is located at a second position (FIG. 3) where the support portion 44opens the opening 20.

The ultrasound probe 17 is provided on the outside of the supportportion 44. The ultrasound probe 17 is a so-called phased array type, inwhich a plurality of elements are arranged along the circumferentialdirection 102 on the outer peripheral surface of the support portion 44.The number of the elements is not particularly limited. However, whenthe elements are arranged corresponding to the number of the elementsprovided on the half of the circumference of the IVUS shaft 16, forexample, 32 elements are arranged in the circumferential direction. Whenthe elements are electrically ignited in order, tomographic images of ablood vessel around the ultrasound probe 17 are collected. A cable 45 isconnected to the elements of the ultrasound probe 17. The cable 45 isinserted into and passed through the internal space of the IVUS shaft16, extended to the outside from the proximal end, and then connected tothe control device 18. The control device 18 is one which supplieselectric power to the ultrasound probe 17 and forms tomographic imagesbased on electric signals obtained from the ultrasound probe 17 and is aknown control device for use in intravascular ultrasound (IVUS).

Although not illustrated in each figure, the IVUS shaft 16 may beprovided with a fitting structure which regulates the movement in thecircumferential direction in such a manner that the IVUS shaft 16 doesnot relatively rotate in the circumferential direction (around the axialdirection 101) with respect to the shaft 11 and can relatively move onlywith respect to the axial direction 101. Due to the fact that thefitting structure or the like is provided, the position of the notchportion 43 of the IVUS shaft 16 and the position of the ultrasound probe17 are not displaced with respect to the circumferential direction 102of the shaft 11.

[Usage Directions for Catheter 10]

Hereinafter, the usage directions for the catheter 10 are described withreference to FIGS. 3 and 4.

The catheter 10 is used when excising an atheroma 51 formed in the innerwall of a blood vessel 50. The position of the atheroma 51 is confirmedby the IVUS or the like beforehand. The catheter 10 is inserted into theblood vessel 50 from the distal end portion 13 in the state (FIG. 1)where the balloon 23 is contracted. Although not illustrated in eachfigure, a guide wire is inserted into the blood vessel 50 beforehand inthe insertion of the catheter 10 into the blood vessel 50. The insertionof the guide wire into the blood vessel 50 is performed by a knowntechnique. The catheter 10 is inserted into the blood vessel 50 from thedistal end portion 13 while inserting the guide wire, which is insertedinto the blood vessel 50, into the internal space of the distal end tip33 of the distal end portion 13, the internal space of the shaft 11, thethrough-hole of the cutting portion 21 of the cutter 12, and then theinternal space of the shaft 22 in order.

The distal end portion 13 is advanced to the atheroma 51 in the bloodvessel 50 while being elastically curved along the guide wire at aportion where the blood vessel 50 is curved, such as coronary arteries.When the distal end portion 13 reaches the atheroma 51, so that theopening 20 of the shaft 11 faces the atheroma 51, the insertion of theshaft 11 into the blood vessel 50 is ended. By moving the supportportion 44 of the IVUS shaft 16 to the first position where the supportportion 44 covers the opening 20, and then electrically igniting theultrasound probe 17, tomographic images of the blood vessel 50 includingthe opening 20 are collected. By confirming the formed tomographicimages of the blood vessel 50 by the control device 18, it can beconfirmed that the opening 20 has reached a position corresponding tothe position of the atheroma 51 and the state of the atheroma 51 can beconfirmed. Thereafter, the guide wire is drawn out of the proximal endportion 14 side of the catheter 10. The actuator 15 is connected to theshaft 22 of the cutter 12.

As illustrated in FIG. 3, in the state where the opening 20 of the shaft11 faces the atheroma 51 and where the support portion 44 is located atthe second position where the support portion 44 of the IVUS shaft 16opens the opening 20, the balloon 23 in the contracted state is expandedby fluid which is caused to flow into the tube body for balloon 24 fromthe port 41. When the expanded balloon 23 abuts on the inner wall of theblood vessel 50 on a side opposite to the atheroma 51, the opening 20 isstuck to the atheroma 51, so that the atheroma 51 partially enters theinternal space of the shaft 11 from the opening 20. In the state above,the catheter 10 is fixed to the blood vessel 50.

Subsequently, a motor of the actuator 15 is driven, so that the cuttingportion 21 is rotated through the shaft 22 of the cutter 12. Due to thefact that the shaft 22 is advanced to the distal end side in the axialdirection 10 with respect to the shaft 11 on the proximal end portion 14side, the rotating cutting portion 21 abuts on the atheroma 51, so thatthe atheroma 51 is excised by the cutting portion 21. Fragments 52 ofthe excised atheroma 51 enter the internal space of the blade tube 31through the internal space of the shaft 11.

After the atheroma 51 is excised by the cutter 12, the support portion44 of the IVUS shaft 16 is located at the first position where thesupport portion 44 covers the opening 20. Then, the ultrasound probe 17is electrically ignited, whereby tomographic images of the blood vessel50 in the state where the atheroma 51 is excised are collected. Thus,the state where the atheroma 51 is excised can be immediately confirmed,i.e., without drawing out the catheter 10 from the blood vessel 50.Therefore, when the excision of the atheroma 51 is insufficient, forexample, the support portion 44 of the IVUS shaft 16 is located at thesecond position again, and then the remaining atheroma 51 can be excisedby the cutter 12. The collection of the tomographic images of the bloodvessel 50 may be performed by electrically igniting the ultrasound probe17 while moving the IVUS shaft 16 in the axial direction 101 withrespect to the shaft 11. Thus, the tomographic images are continuouslycollected in the length direction (which is almost in agreement with theaxial direction 101) of the blood vessel 50. Then, when the excision ofthe atheroma 51 is completed, the balloon 23 is contracted, and then thecatheter 10 is drawn out of the blood vessel 50 to be collected.

[Operational Effects of First Embodiment]

According to the catheter 10 of the first embodiment, the atheroma 51 inthe blood vessel 50 can be excised and the ultrasonic images of theblood vessel 50 can be obtained by the simple structure.

Moreover, since the IVUS shaft 16 can be relatively moved in the axialdirection 101 with respect to the shaft 11 and the ultrasound probe 17can be moved in the length direction (axial direction 101) in the bloodvessel 50 in connection with the relative movement, the ultrasound probe17 can be moved with respect to the atheroma 51, so that tomographicimages different in the position in the length direction of the bloodvessel 50 can be obtained.

Moreover, the notch portion 43 is provided in the IVUS shaft 16, andtherefore even when the support portion 44 provided on the side oppositeto the notch portion 43 is located at the first position where thesupport portion 44 covers the opening 20, the balloon 23 which isoutwardly expanded and the IVUS shaft 16 do not abut on each other bythe notch portion 43. Therefore, in the support portion 44 at the firstposition, tomographic images including the atheroma 51 at a positionfacing the opening 20 can be obtained.

Modification of First Embodiment

In the first embodiment described above, although the ultrasound probe17 is provided in the IVUS shaft 16, the IVUS shaft 16 may not beprovided and the ultrasound probe 17 may be provided on the outerperipheral surface of the shaft 11.

As illustrated in FIG. 5, the ultrasound probe 17 is provided in thevicinity of the opening 20 in the shaft 11 and is provided on the distalend side relative to the opening 20. In this modification, theultrasound probe 17 and the balloon 23 are arranged in such a manner asnot to interfere with each other, the ultrasound probe 17 may have 32elements corresponding to the number of the elements provided on thehalf of the circumference of the shaft 11 as in the first embodimentdescribed above or may have 64 elements corresponding to the number ofthe elements provided on the entire circumference of the shaft 11.Although not illustrated in FIG. 5, the cable 45 extended from theultrasound probe 17 is inserted into and passed through the internalspace of the shaft 11 to be connected to the control device 18. Asillustrated in FIG. 6, the ultrasound probe 17 may be provided in thevicinity of the opening 20 in the shaft 11 and on the proximal end siderelative to the opening 20.

Since the IVUS shaft 16 is not provided according to such amodification, a reduction in size, particularly a reduction in diameter,of the catheter 10 is achieved, and the structure becomes simpler. Bydeflating the balloon 23 and moving the ultrasound probe 17 in thelength direction of the blood vessel 50 together with the catheter 10,tomographic images of the blood vessel 50 containing the atheroma 51 andtomographic images continuing in the length direction of the bloodvessel 50 can be collected. Moreover, due to the fact that theultrasound probe 17 is provided over the entire circumference of theshaft 11, tomographic images of the entire circumference of the bloodvessel 50 can be collected.

Second Embodiment

As illustrated in FIGS. 7 and 8, a catheter 210 has a shaft 211 (whichis equivalent to the tube body), a torque shaft 216 and a cutter 212provided in the shaft 211, a distal end portion 213 configuring thedistal end of the shaft 211, a proximal end portion 214 connected to theproximal end of the shaft 211, an actuator 215 which gives rotation tothe cutter 212, an OCT image wire 217 (which is equivalent to the lightguide material) and a reflective material 218 provided in the torqueshaft 216, and a guide wire tube 219. The catheter 210 is used as amedical instrument which is inserted into a blood vessel to excise anatheroma or photographs ultrasonic images of a blood vessel.

The shaft 211 is a tube capable of containing the cutter 212thereinside. The shaft 211 is configured from a surgical stainless steelcircular tube or a synthetic resin circular tube, for example, and hasflexibility which allows the shaft 211 to be elastically curvedcorresponding to the curved shape of a blood vessel. The distal end andthe proximal end of the shaft 211 each are opened. The outer diameter ofthe shaft 211 is set according to the inner diameter of a blood vesselinto which the shaft 211 is to be inserted, e.g., coronary arteries. Theinner diameter of the shaft 211 is set according to the outer diameterof the cutter 212. The outer diameter and the inner diameter of theshaft 211 are almost uniform over the axial direction 101 of the shaft211. The length in the axial direction 101 of the shaft 211 is set inconsideration of the length from catheter insertion portions, such asthe human limbs, to the affected portion.

As illustrated in FIG. 8, an opening 220 is formed in the vicinity ofthe distal end portion 213 in the shaft 211. The opening 220 is formedby cutting out a part of the side wall of the shaft 211. The shape andthe size of the opening 220 are set in consideration of the shape andthe size of an atheroma which is probably formed in the affectedportion.

As illustrated in FIG. 8, the cutter 212 is provided in the vicinity ofthe opening 220 in the internal space of the shaft 211. The cutter 212has an approximately cylindrical shape and the outer diameter is alittle smaller than the inner diameter of the shaft 211. Therefore, thecutter 212 can move along the axial direction 101 in the internal spaceof the shaft 211. On the distal end side of the cutter 212, a pluralityof blades are formed in such a manner as to radially extend from thecenter. Although not illustrated in FIG. 8, a through-hole is formedalong the axial direction 101 in the center of the cutter 212.

The torque shaft 216 is inserted into and passed through the internalspace of the shaft 211. The distal end side thereof is connected to thecutter 212, and the proximal end side thereof is extended to the outsideof the proximal end portion 214 of the shaft 211. The torque shaft 216has flexibility which allows the torque shaft 216 to be elasticallycurved corresponding to the curved shape of a blood vessel together withthe shaft 211 and has torsional rigidity which transmits rotation aroundthe axial direction 101. The torque shaft 216 is configured to form atube shape as a whole by continuing surgical stainless steel in a spiralshape, for example.

As illustrated in FIG. 7, the torque shaft 216 is connected to theactuator 215. Due to the fact that the torque shaft 216 receives drivetransmitted from the actuator 215 to rotate, the cutter 212 rotates. Dueto the fact that the torque shaft 216 is moved in the axial direction101, the cutter 212 moves in the axial direction 101 in the internalspace of the shaft 211.

As illustrated in FIG. 8, an opening 221 is formed in the vicinity ofthe distal end connected to the cutter 212 in the torque shaft 216. Theopening 221 is formed by cutting out a part of the side wall of thetorque shaft 216. The shape and the size of the opening 221 are set inconsideration of the shape and the size of near-infrared rays which arereflected by the reflective material 218 to be emitted in a directionorthogonal to the axial direction 101.

As illustrated in FIG. 8, an OCT image wire 217 is inserted into andpassed through the internal space of the torque shaft 216 from theproximal end portion 214 to be extended to the opening 221. The innerdiameter of the internal space of the torque shaft 216 is equivalent tothe outer diameter of the OCT image wire 217. Therefore, the axis of theOCT image wire 217 and the axis of the torque shaft 216 are almost inagreement with each other. Although not illustrated in detail in eachfigure, the OCT image wire 217 is one in which an optical fiber is builtin a transparent outer casing and which is provided with a lens emittingnear-infrared rays on a distal end portion. The near-infrared raysemitted from the lens are emitted along the axial direction of the OCTimage wire 217. The OCT image wire 217 propagates near-infrared rays tobe supplied from a light source built in an OCT body display portion 222to the distal end side.

In the internal space of the torque shaft 216, the reflective material218 is disposed facing the distal end of the OCT image wire 217 in theaxial direction 101. In the reflective material 218, a reflectivesurface 225 facing the distal end of the OCT image wire 217 is a surfaceinclined to form an angle of 45° with respect to the axis of the OCTimage wire 217. The reflective surface 225 is exposed to the outside ofthe torque shaft 216 through the opening 221 of the torque shaft 216.The reflective material 218 is a columnar body containing an opticalfiber, resin, or the like. The outer diameter thereof is equivalent tothe inner diameter of the internal space of the torque shaft 216.Therefore, the axis of the reflective material 218 and the axis of thetorque shaft 216 are almost in agreement with each other. On a surfaceincluding the reflective surface 225 of the reflective material 218,metal layers are laminated. The metal layer is formed by, for example,plating or sputtering nickel, gold, aluminum, chromium, and the likealone or a mixture thereof onto the surface of the reflective material218. By the reflective surface 225, near-infrared rays emitted along theaxial direction 101 from the OCT image wire 217 are reflected in adirection (second direction) orthogonal to the axial direction 101 to beemitted to the outside of the torque shaft 216 through the opening 221.The angle of the reflective surface 225 with respect to the axis of theOCT image wire 217 is an example and may not necessarily be 45°. Morespecifically, the near-infrared rays to be emitted along the axialdirection 101 from the OCT image wire 217 may be reflected in adirection crossing the axial direction 101.

The OCT image wire 217 and the reflective material 218 can rotate aroundthe axis (axial direction 101) integrally with the torque shaft 216 andcan slide in the axial direction 101 in a state of holding the mutualpositional relationship, i.e., the clearance and the angle of thereflective surface 225. The rotation and the slide of the OCT image wire217 and the reflective material 218 are controlled by directly orindirectly operating the proximal end side of the torque shaft 216extended from the proximal end portion 214. Specifically, driving forcefrom the actuator 215 is given to the proximal end side of the torqueshaft 216, whereby the torque shaft 216 is rotated and slid.

As illustrated in FIGS. 7 and 8, a balloon 223 is provided at a positionopposite to the opening 220 with respect to the axis of the shaft 211.The balloon 223 can outwardly expand from the side wall of the shaft 211and is folded and stuck to the side wall of the shaft 211 until thecatheter 210 is inserted into a blood vessel. As raw materials of theballoon 223, materials having biocompatibility are preferable. Specificexamples of the materials include polyurethane, polyethylene, polyester,polypropylene, polyamide, polyamide elastomer, polytetrafluoroethylene,polyvinylidene fluoride, and the like.

As illustrated in FIG. 8, the proximal end side of the balloon 223 isconnected to a tube for balloon 224 provided along the side wall of theshaft 211. The internal space of the tube for balloon 224 is caused tocommunicate with the internal space of the balloon 223. The tube forballoon 224 is extended to the proximal end portion 214 and the internalspace of the tube for balloon 224 is connected to a port 241 of theproximal end portion 214. Due to the fact that liquid, such asphysiological saline, injected from the port 241 of the proximal endportion 214 flows into the balloon 223, the balloon 223 is expanded in ablood vessel. The tube for balloon 224 is a molded body of flexibleplastic which can be elastically deformed, such as polyamide, polyamideelastomer, and polyetheramide.

As illustrated in FIGS. 7 and 8, the distal end portion 213 is connectedto the distal end of the shaft 211. As illustrated in FIG. 8, the distalend portion 213 has a blade tube 231, a reduced diameter portion 232,and a distal end tip 233.

As illustrated in FIGS. 7 and 8, the blade tube 231 is a circular tubein which both sides are opened. The blade tube 231 is connected to thedistal end of the shaft 211 and the internal space thereof is caused tocommunicate with the internal space of the shaft 211. The blade tube 231is one in which flexible plastic which can be elastically deformed, suchas polyamide, polyamide elastomer, and polyetheramide, is reinforcedwith a core material 234. The core material 234 is embedded in the sidewall of the blade tube 231. The core material 234 is formed into acylindrical shape by braiding wire rods, such as surgical stainlesssteel, into a mesh. The inner diameter of the blade tube 231 is almostequal to the outer diameter of the shaft 211 and the blade tube 231 isfitted to the distal end of the shaft 211 from the outside. The outerdiameter and the inner diameter of the blade tube 231 are almost uniformover the axial direction 101. In each figure other than FIG. 7, the corematerial 234 is not illustrated.

As illustrated in FIGS. 7 and 8, the reduced diameter portion 232 is acircular tube in which the blade tube 231 side is opened and the outerdiameter decreases toward the distal end in a tapered shape. The reduceddiameter portion 232 is connected to the distal end of the blade tube231 and the internal space thereof is caused to communicate with theinternal space of the blade tube 231. The reduced diameter portion 232contains flexible plastic which can be elastically deformed, such aspolyamide and polyetheramide. The inner diameter on the proximal endside of the reduced diameter portion 232 is almost equal to the outerdiameter of the distal end of the blade tube 231. The reduced diameterportion 232 is fitted to the distal end of the blade tube 231 from theoutside, and then thermally fused thereto. The distal end side of thereduced diameter portion 232 is sealed. The thickness decreases towardthe distal end side on the distal end side of the reduced diameterportion 232.

As illustrated in FIGS. 7 and 8, the distal end tip 233 is connected tothe distal end of the reduced diameter portion 232. A distal end 235 ofthe distal end tip 233 is projected from the distal end of the reduceddiameter portion 232 to the outside in the axial direction 101. Thedistal end tip 233 contains flexible plastic which can be elasticallydeformed, such as polyamide and polyetheramide. The distal end tip 233is thermally fused on the distal end side of the reduced diameterportion 232. On the distal end of the distal end tip 233, a marker whichcan be confirmed by X-rays or the like may be provided.

As illustrated in FIG. 7, a guide wire tube 219 is provided over thedistal end tip 233, the blade tube 231, and a part of the distal endside of the shaft 211 along the outer peripheral surface of each of thedistal end tip 233, the blade tube 231, and the distal end of the shaft211. The guide wire tube 219 is a molded body of flexible plastic whichcan be elastically deformed, such as polyamide, polyamide elastomer, andpolyetheramide. The guide wire tube 219 is disposed at a position wherethe guide wire tube 219 is not overlapped with the opening 220 of theshaft 211 and the balloon 223, e.g., in the vicinity of the boundarybetween the shaft 211 and the balloon 223. The internal space of theguide wire tube 219 is a guide wire lumen, and a guide wire which is notillustrated is inserted into and passed through the guide wire lumen.

The proximal end portion 214 is provided on the proximal end of theshaft 211. The proximal end portion 214 is a cylindrical member havingan internal space continuing to the internal space of the shaft 211. Theproximal end portion 214 is a molded body of resin, such aspolypropylene or ABS. The proximal end portion 214 may serve as a handlein an operation of inserting and removing the shaft 211 into/from ablood vessel.

The proximal end portion 214 is provided with the port 241 extended in adirection crossing the axial direction 101. Another device, such as asyringe, is connected to the port 241, and then fluid, such asphysiological saline, which is flown in and out from the device, flowsin and out of the tube for balloon 224 from the proximal end portion214. The proximal end portion 214 may be provided with another portcontinuing to the internal space of the shaft 211. Such a port is usedfor the purpose of, for example, collecting an excised atheroma enteringthe inside of the shaft 211.

From an opening on the proximal end side of the proximal end portion214, the torque shaft 216 is extended. The actuator 215 is connected tothe torque shaft 216. In the actuator 215, a motor, a battery, and thelike are built. To the torque shaft 216, rotation of the motor of theactuator 215 is transmitted.

The OCT image wire 217 disposed in the internal space of the torqueshaft 216 is connected to the OCT body display portion 222 through theactuator 215. The OCT body display portion 222 has a light source whichsupplies near-infrared rays, an interferometer, a portable referencemirror, a monitor, an arithmetic unit, and the like. Near-infrared rayssupplied from the light source are split by the interferometer to besupplied to each of the OCT image wire 217 and the portable referencemirror. Then, near-infrared rays reflected in a blood vessel andnear-infrared rays reflected on the portable reference mirror arecombined in the interferometer. Interference signals of thenear-infrared rays are treated by the arithmetic unit to be displayed astomographic images of the blood vessel on a monitor.

[Usage Directions for Catheter 210]

Hereinafter, the usage directions for the catheter 210 are describedwith reference to FIGS. 9 and 10.

The catheter 210 is used when excising an atheroma 51 formed in theinner wall of a blood vessel 50. The position of the atheroma 51 isconfirmed by the blood vessel tomographic images by the OCT. Thecatheter 210 is inserted into the blood vessel 50 from the distal endportion 213 in the state (FIG. 7) where the balloon 223 is contracted.Although not illustrated in each figure, a guide wire is inserted intothe blood vessel 50 beforehand in the insertion of the catheter 210 intothe blood vessel 50. The insertion of the guide wire into the bloodvessel 50 is performed by a known technique. The catheter 210 isinserted into the blood vessel 50 from the distal end portion 213 whileinserting the guide wire inserted into the blood vessel 50 into a guidewire tube 219.

The distal end portion 213 is advanced to the atheroma 51 in the bloodvessel 50 while being elastically curved along the guide wire at aportion where the blood vessel 50 is curved, such as coronary arteries.When the distal end portion 213 reaches the atheroma 51, and the opening220 of the shaft 211 faces the atheroma 51, the insertion of the shaft211 into the blood vessel 50 is ended. By rotating the torque shaft 216by the actuator 215 and supplying near-infrared rays to the OCT imagewire 217 from the OCT body display portion 222, tomographic images ofthe blood vessel 50 are displayed in the OCT body display portion 222.By confirming the tomographic images of the blood vessel 50, it can beconfirmed that the opening 220 has reached the position corresponding tothe atheroma 51 and the state of the atheroma 51 can be confirmed.Thereafter, the guide wire is drawn out of the proximal end portion 214side of the catheter 210. The actuator 215 is connected to the torqueshaft 216 of the cutter 212. In FIGS. 9 and 10, the guide wire isomitted.

In the state where the opening 220 of the shaft 211 faces the atheroma51 as illustrated in FIG. 9, the balloon 223 in the contracted state isexpanded by fluid which is caused to flow into the tube for balloon 224from the port 241. When the expanded balloon 223 abuts on the inner wallof the blood vessel 50 on a side opposite to the atheroma 51, theopening 220 is stuck to the atheroma 51, so that the atheroma 51partially enters the internal space of the shaft 211 from the opening220. In the state above, the catheter 210 is fixed to the blood vessel50.

Subsequently, the rotation of the actuator 215 is transmitted to thecutter 212 through the torque shaft 216 of the cutter 212, so that thecutter 212 is rotated. Due to the fact that the torque shaft 216 isadvanced to the distal end side in the axial direction 10 with respectto the shaft 211 on the proximal end portion 214 side, the rotatingcutter 212 abuts on the atheroma 51, so that the atheroma 51 is excisedby the cutter 212. Fragments 52 of the excised atheroma 51 enter theinternal space of the blade tube 231 through the internal space of theshaft 211.

After the atheroma 51 is excised by the cutter 212, tomographic imagesof the blood vessel 50 in the state where the atheroma 51 is excised canbe obtained by the same OCT as above. Thus, the state where the atheroma51 is excised can be immediately confirmed, i.e., without drawing outthe catheter 210 from the blood vessel 50. Therefore, when the excisionof the atheroma 51 is insufficient, for example, the remaining atheroma51 can be excised by rotating the cutter 212. The collection of thetomographic images of the blood vessel 50 may be performed while movingthe reflective material 218 together with the torque shaft 216 in theaxial direction 101 with respect to the shaft 211. Thus, the tomographicimages continuing in the length direction (which is almost in agreementwith the axial direction 101) of the blood vessel 50 can be obtained.Then, when the excision of the atheroma 51 is completed, the balloon 223is contracted, and then the catheter 210 is drawn out of the bloodvessel 50 to be collected.

[Operational Effects of Second Embodiment]

According to the catheter 210 of the second embodiment, the atheroma 51in the blood vessel 50 can be excised and the ultrasonic images of theblood vessel 50 can be obtained by the simple structure.

Moreover, since the OCT image wire 217 and the reflective material 218are disposed in the internal space of the torque shaft 216,near-infrared rays can be guided to the vicinity of the atheroma 51 inthe blood vessel 50 to be reflected in the torque shaft 216.

Moreover, since the OCT image wire 217 and the reflective material 218can be rotated integrally with the torque shaft 216, the excision of theatheroma 51 and the OCT can be realized by controlling the number ofrotations of the motor in the actuator 215.

Moreover, since the OCT image wire 217 and the reflective material 218can move along the axial direction 101 integrally with the torque shaft216, tomographic images of the blood vessel 50 along the axial direction101 can be obtained.

Moreover, since the OCT image wire 217 and the reflective material 218are disposed in the internal space of the torque shaft 216, the OCTimage wire 217 and the reflective material 218 are covered with thetorque shaft 216 to be protected.

Moreover, since the guide wire tube 219 is provided along the shaft 211,the catheter 210 can be inserted into the blood vessel 50 along a guidewire.

Modification

In the embodiments described above, although the guide wire tube 219 hasa so-called rapid exchange type structure in which the guide wire tube219 is disposed on the outside of the shaft 211. However, as illustratedin FIG. 11, a so-called over-the-wire type structure in which theinternal space of the torque shaft 216 is used as a guide wire lumen maybe adopted.

When the over-the-wire type structure is adopted, the OCT image wire 217and the reflective material 218 are disposed in such a manner as to faceeach other with respect to the axial direction 101 along the outerperipheral surface of the torque shaft 216 as illustrated in FIG. 11.Near-infrared rays to be emitted along the axial direction 101 from theOCT image wire 217 are reflected by the reflective material 218 in adirection (direction orthogonal to) crossing the axial direction 101toward the outside of the torque shaft 216. Thus, the near-infrared raysare not emitted to the guide wire inserted into and passed through theinternal space of the torque shaft 216. In the over-the-wire typestructure, the opening 221 does not need to be formed in the torqueshaft 216.

When the over-the-wire type structure is adopted, a circular tube, inwhich both sides are opened and the outer diameter of a proximal end 236side increases in a tapered shape as illustrated in FIG. 11 is adoptedas the distal end tip 233. The distal end tip 233 is connected to thedistal end of the reduced diameter portion 232 and the internal spacethereof is caused to communicate with the internal space of the reduceddiameter portion 232. A distal end 235 of the distal end tip 233 isprojected from the distal end of the reduced diameter portion 232 to theoutside in the axial direction 101. The proximal end 236 side of thedistal end tip 233 is extended in the axial direction 101 in theinternal space of the reduced diameter portion 232 and the proximal end236 reaches the internal space of the blade tube 231. More specifically,a portion including a distal end side portion of the blade tube 231 andthe reduced diameter portion 232 has a double tube structure in whichthe blade tube 231 and the reduced diameter portion 232 serve as theouter side and the distal end tip 233 serves as the inner side.

Although the diameter of the distal end tip 233 is increased on theproximal end 236 side, the other outer diameter and the inner diameterof the other portion are almost uniform. The outer diameter of theuniform portion is smaller than the inner diameter of the blade tube 231and is almost equal to the inner diameter of the distal end of thereduced diameter portion 232. Although the diameter of the proximal end236 side is increased, the maximum diameter is smaller than the innerdiameter of the blade tube 231.

A through-hole along the axial direction 101 is formed in the cutter212. A guide wire lumen is formed along the axial direction 101 of theshaft 211 by the internal space of the torque shaft 216, thethrough-hole of the cutter 212, the internal space of the blade tube231, and the internal space of the distal end tip 233.

The distal end surface of the OCT image wire 217 may be a surfaceinclined to form an angle of 45° with respect to the axial direction 101and the reflective material 218 may be provided on the distal endsurface. In that case, the reflective material 218 disposed at aposition apart from the OCT image wire 217 is not present.

REFERENCE SIGNS LIST

-   10 Catheter-   11 Shaft (Tube body)-   12 Cutter-   16 IVUS shaft (Outer tube body)-   17 Ultrasound probe-   20 Opening-   23 Balloon-   43 Notch portion-   44 Support portion-   210 Catheter-   211 Shaft (Tube body)-   212 Cutter-   216 Torque shaft-   217 OCT image wire (Light guide material)-   218 Reflective material-   219 Guide wire tube (Guide wire lumen)-   220,221 Opening-   223 Balloon

1. A catheter comprising: a tube body having an opening in a part of aside wall on a distal end side; a cutter which is located in a vicinityof the opening in an internal space of the tube body and which can movein an axial direction of the tube body; a balloon which is disposed on aside opposite to the opening with respect to an axis of the tube bodyand which outwardly expands from the side wall of the tube body; and aphased array ultrasound probe disposed along a circumferential directionof an outer peripheral surface of the side wall in the vicinity of theopening at least on a same side as a side where the opening is providedwith respect to the axis of the tube body.
 2. The catheter according toclaim 1, further comprising: an outer tube body which is provided on anoutside of the tube body and which can relatively move in the axialdirection with respect to the tube body, wherein the ultrasound probe isprovided in the outer tube body.
 3. The catheter according to claim 2,wherein the outer tube body has: a notch portion in which a partcorresponding to the balloon is cut out; and a support portion which isdisposed on a side opposite to the notch portion with respect to theaxis of the outer tube body and which can be moved to a first positionwhere the support portion covers the opening and a second position wherethe support portion opens the opening by the relative movement, whereinthe ultrasound probe is provided on the support portion, and the notchportion does not abut on the balloon in a state of being outwardlyexpanded at the first position.
 4. The catheter according to claim 1,wherein the ultrasound probe is fixed on a distal end side relative tothe opening in the tube body.
 5. The catheter according to claim 1,wherein the ultrasound probe is fixed on a proximal end side relative tothe opening in the tube body.
 6. A catheter comprising: a tube bodyhaving an opening in a part of a side wall on a distal end side; acutter which is located in a vicinity of the opening in an internalspace of the tube body and which can move in an axial direction of thetube body; a torque shaft which is inserted into and passed through theinternal space of the tube body and is connected to the cutter in such amanner as to be able to transmit a rotation torque to the cutter; alight guide material provided along the torque shaft; a reflectivematerial which reflects light emitted from the light guide material in asecond direction crossing a first direction in which the light guidematerial is extended; and a balloon which is disposed on a side oppositeto the opening with respect to an axis of the tube body and outwardlyexpands from the side wall of the tube body.
 7. The catheter accordingto claim 6, wherein the light guide material and the reflective materialare disposed in an internal space of the torque shaft, and thereflective material emits light reflected in the second direction to anoutside of the torque shaft through the opening formed in the side wallof the torque shaft.
 8. The catheter according to claim 6, wherein thelight guide material and the reflective material can be rotatedintegrally with the torque shaft.
 9. The catheter according to claim 6,wherein the light guide material and the reflective material can moveintegrally with the torque shaft along the first direction.
 10. Thecatheter according to claim 6, wherein the light guide material and thereflective material are disposed in the internal space of the torqueshaft.
 11. The catheter according to claim 6, wherein the light guidematerial and the reflective material are disposed on an outer peripheralsurface side of the torque shaft.
 12. The catheter according to claim 6,wherein a guide wire lumen is provided along the tube body.